Got my car back today running significantly better (for now at least, problem is/was intermittent) mechanic checked fuel pressure all within spec, compression tested cylinders within spec albeit slightly different across the 4 bores (car is nearly 20 years old so not surprising). Checked and recalibrated TPS which he said was slightly off, replaced fuel filter and advised me to steer clear of Shell 98 and stick with BP Ultimate 98 (AU market names) fuel. He also regapped spark plugs to 1 mm or just under to try and reduce spark time thus increasing number or sparks per second to burn more fuel as it is a town driven car, not a racing machine.
Seems like much of the problem lies in basic tuning neglect over the years rather than specific failure of any one part considering new o2 sensor also improved problem but did not rid of it completely.
Whilst car is 100% better than it was it still doesn't run perfectly but mechanic reckons that is fuel quality related and possibly the slowing down in response time from the fuel injector relay under the dash which controls fuel injector solenoid operation and speed.
Proverbial food for thought.